The goal of this project is to describe respiratory and gastrointestinal infections o( the elderly, focusing on infections that are suspected of causing. significant illness but about which clinical and epidemiological Information is lacking. The specific aims are: 1) to monitor over a 8-year period the infectious disease experience of samples of urban elder!y aged 65 and over; 2) to compare patterns of viral and other infections among samples of elderly community resident, members of communal residences for the elderly, and elderly women who are regularly engaged in the care of small children; 3) to attempt to measure the incidence and prevalence of specific infections, including influenza A and B, parainfluenza 1, 2 and 3, adenovirus, respiratory syncytial virus, rotavirus and Mycoplasma pneumoniae; and 4) to establish a serum bank for future serologic studies. Three samples of persons aged 65 and over will be observed for 8 years: 300 non-institutionalized, 100 communal-living, and 100 women who care for small children. Blood samples for serological study will be obtained at intake and 3 times a year on all subjects, and paired acute and convalescent sera will be obtained at the time of any acute respiratory or gastrointestinal infection. A surveillance system, consisting. of regular visits and Illness visits by nurse-practitioners plus regular telephone contacts, will be established, and samples will be obtained at the time of illness for laboratory diagnostic studies aimed at detecting the organisms named. Results of the study will be used to examine the relationship between patterns of infection in the elderly and the characteristics of their interpersonal contacts, particularly with young children. The data base to be developed by this study is also expected to be useful for planning and developing future prophylactic and treatment programs, following in the tradition of the Cleveland Family Study (1948-57), on which the project modeled.